I have known Chief Inspector Japp of Scotland Yard for some quarter of a century. He had been involved in many of Poirot’s old cases. In my accounts of these, I usually referred to him as ‘our old friend, Inspector Japp’,  and Poirot certainly had some affection for ‘ce pauvre Japp‘, as he referred to him.

I have to admit that there have been occasions when my own feelings toward him were somewhat mixed. If he ever chose to recognise my presence, some of his comments about my powers of observation could be disparaging to say the least, and although he might sometimes acknowledge those of Poirot, as often as not he would indicate that the ‘old boy was getting past it.’

Japp’s corny jokes and put-downs were easily ignored in the presence of a genius such as Poirot, but I did wonder whether they might not grate in his absence. Such were my thoughts as he came through the door, but I forced a smile of greeting.

“Good Lord, if it ain’t Captain Hastings!” He greeted me warmly, and I must admit that we had not met for a few years. He was wearing the brown coat that seemed to accompany him everywhere. I noted that his moustaches were flecked with grey, but it was the same old Japp.

“Hello, Inspector,” I replied somewhat stiffly. “I didn’t expect to see you round here.”

“No more did I,” he said genially. “But when I got the message this morning asking me to call in on Whitehaven Mansions, I didn’t think twice. Don’t know why – busy man these days. Habit, I suppose.”

“It never did you any harm in the past,” I said coldly, calling to mind the countless times that he had needed Poirot’s assistance to avoid making a blunder.

“Hello, what’s all this? I was expecting a warmer reception than that,” said Japp, evidently hurt. “We go back a long way.”

“We certainly do,” I agreed. Japp looked at me curiously, and pondered a minute.

“It’s been a difficult time for you hasn’t it?” he said.

I did not reply, and there was an uncomfortable silence, eventually broken by Miss Lemon, who re-entered with the inevitable tea-tray. She set it down on a coffee table and pulled up a straight-backed chair. Japp removed his coat, tossed his hat on to a hook and sat on the settee, looking eager to get on with things. Feeling somewhat chastened by my unfriendly greeting, I sat down next to him.

‘First of all,’ Miss Lemon began, ‘may I thank the Chief Inspector for coming. I had no right to expect it, but if I had just gone to the police in the normal way they may not have been interested in what are only, at least for now, suspicions.’

‘Not at all,’ said Japp graciously.’ I would have made sure they listened. Moosior Poirot always told me that, although you never said much, and speculated even less, when you did speak it was always worth hearing.’

‘Quite,’ she said. ‘He made the same observation to me. I have to say that, at the moment, my thoughts are horribly close to speculation. I would dismiss them were it not that they concern the one thing I am certain about – my filing system.’

‘I call it Colossus,’ I whispered to Japp.

‘If I could just tell the Chief Inspector my story without interruptions, it will be quicker.’ Suitably admonished, I sat back and listened.

‘In July of this year,’ she continued, ‘I was struck down by a summer flu, a vicious strain that incapacitated me for a couple of weeks, during which time I could not come into work.

‘Towards the end of the month I received a message from M Poirot that he had gone away to Styles St Mary for a rest cure; he himself had not been well, almost an invalid. I would have counselled him against travelling but he had hired a manservant to take with him and he assured me that he would be properly cared for there.

‘I returned here in early August but M Poirot still had not returned. As you know, I was never to see him again.’

She paused for a moment, and I believe we all took a moment to remember our old friend. Outside, all was quiet apart form a single bell tolling.

‘Anyway, when I arrived back heret, here was a pile of correspondence in the letter box and one envelope on the table, marked ‘BY HAND’. I thought this slightly curious, but presumed it must have been delivered by someone with access to a key, such as the landlord, or even Captain Hastings -‘

‘Me!’ I exclaimed. ‘I haven’t set foot inside this place for half a dozen years.’

‘Which I now realise. I put the letter to one side, and started working through the rest of the correspondence. During the next day or so, many more letters arrived, usually from people who had heard of M Poirot’s death. I dealt with those, coming in for an hour or so each day. In the meantime I started looking for work elsewhere.

‘Then M Poirot’s solicitors contacted me, asking me to send my late employer’s files to them by registered post so that they could start to put his affairs in order. As I told Captain Hastings yesterday, I refused. You of all people should understand why, Chief Inspector.’

‘Lord A, Count A and Lord D spring to mind.’ said Japp, dryly. ‘Poirot was party yo many secrets that could prove to be dynamite in the wrong hands.’

‘Quite,’ said Miss Lemon/ ‘I said I was quite prepared to seek out specifics for them, but they weren’t having that. They gave me to understand that my contract was to be terminated forthwith; they were going to send over an agent and I was to hand over the files and keys to him.

‘Now I had heard the name of Captain Hastings – many times! – and I knew that Poirot would have trusted him with his life. So I relaxed, and agreed to meet him yesterday morning. I am glad I did.’ She smiled, and I got a slight tingle up my spine.

‘We agreed to work through the files together, and I had it in mind to remove the extant ones to preserve client confidentiality. When Captain Hastings asked about outstanding correspondence, I remembered the BY HAND letter and showed it to him. It was from a Joe Green. Looking at it again, I realised that it had been typed on my own typewriter here, in this office.  That srtuck me as odd.

‘We were planning to visit the landlords to extend the lease on the flat for a few weeks while we sorted out M Poirot’s affairs, so we decided to ask them whether they had shown anyone around the flat recently and whether anyone had used a typewriter to write this letter.

‘We met a Mr Payne, who denied any knowledge of it.  He also gave us a week’s notice to quit the flat: that too was strange, because I was told only yesterday that there would be no problem extending the lease. Even more curiously, the Mr Payne who had told me that was not the same Mr Payne whom we saw today.’

Japp kept his counsel.

‘None of this would have been sufficient to trouble a man in your position, Chief Inspector, were it not that, earlier this morning, I decided to re-check my files for any mention of a Joe Green – in case my memory had let me down.’

The tone of her voice betrayed the unlikelihood of such an event.

‘And I found something that should not have been there. It was not filed or coded correctly, but I could decipher it. I was shocked. Someone had been tampering with my files, someone who knows far more about them than anyone should. As the apartment had been just about empty for the greatest part of a couple of weeks, I considered that a dangerous turn of events. That is why I called you.’

Japp looked at her keenly. ‘You were right to do so. Before we go any further, may I see the ‘by hand’ letter? Thank you.’

He read it and whistled. ‘Joe Green, eh?’ He got up and walked to the window. ‘Going to rain,’ he said, the turned round and looked at the pair of us appraisingly.

‘This isn’t the first time I have been around Whitehaven Mansions this week,’ Japp said. ‘Yesterday, just around the corner from here, a body of a man was found buried in rubble by a milkman on his rounds.’

I had read about this in the Evening Chronicle.

‘Yes, poor chap,’ I said. ‘ One of those walls must have collapsed on top of him.  There is a lot of bomb damage in this area. It is high time it was cleared up.’

Japp thought for a minute, then seemed to come to a decision.

‘It was not an accident,’ he said. ‘Having heard Miss Lemon’s story, I think I can let you into a secret that the press has not been told. When the body was pulled from under the rubble, there were blood stand on the back of his jacket and holes consistent with a vicious stabbing. The rubble was added afterwards.’

Miss Lemon paused in the act of lifting the teapot.

‘Do you know who he was?’ she asked.

‘No-o-o…’ Japp replied. ‘But there were initials on the label of his jacket that may give us a clue. Initials that now mean something.’

‘JG,’ she surmised.

‘Exactly,’ said Japp. ‘So you can see why you letter from Joe Green might be of interest to us. Let’s say that this Joe Green, or whoever he really is, gets into contact with Poirot a few weeks ago for a consultation. He wants to see him again, but Poirot is away. So, somehow he gets into this flat and types him a message. A strange thing to do, but there must have been a reason for it.

‘Then later he hears that Poirot has died. He decides to return to Whitehaven Mansions but is killed before he arrives. Why would he come back? There must be something that he has left here that he needed to retrieve … unless he had made an appointment with Miss Lemon?’

Japp looked keenly at Miss Lemon but she returned his gaze steadily.

‘The only appointment I had yesterday was with Captain Hastings.’ she said. ‘I have never had any contact with a Joe Green.’

It occurred to me that it might all have been a coincidence and I said so. Japp looked at me pityingly.

‘There’s one other thing I should mention. When the milkman, name of Davy Partridge, started pulling away the rubble he found that ‘JG’  was still  alive. He was groaning, but Partridge thought he could just make out a few words. They didn’t make sense – something like ‘Nemo’, and something else that made Partridge think of the number 0 or zero. Does that suggest anything to you?’

Miss Lemon considered for a minute. Eventually, she shook her head.

‘No. We’ve literally nothing to go on.’

I stared at her suspiciously. Miss Lemon famously wasted no words, Maybe she meant more by what she said, but if so it escaped me.

Japp stood up and reached for his coat.

‘Look, I must be getting on,’ he said. ‘I’ll keep this letter if I may. There’s clearly something going on round here, and I can assure you we will be keeping an eye on this place from now on. In the meantime, I’d be grateful if you would check all the files for any contacts with the initials JG. Joe Green might be an alias. Also, if you find anything else suspicious in your files, or elsewhere in this flat, please call me.’

I shook Japp’s hand and showed him to the door.

‘Looks like we may be hunting together again, Captain Hastings,’ he said, and took his leave.